Should I be worried?

I have a young RES, about 3 1/2 to 4 inches long. I've had her about 4 months or so now and she looks as though she is shedding her skin. There are small bits of what looks like skin hanging from her and some days there are longer strips floating in the water. I was wondering if this really is just shedding of the skin and her growing bigger or if it may be a symptom of something worse. Thanks.